Is there an obesity gene?

Obesity is officially diagnosed when a person’s body mass index (BMI) is over 30. Globally the number of people who are obese is continuing to rise, as unhealthy diets and lack of good physical activity contribute to excessive weight gain. The problem, unfortunately, has reached pandemic levels and costs healthcare organisations millions each year. More importantly, it’s having a huge health impact on individuals who suffer from obesity.

The condition has been shown to increase the risk of cardiovascular disease, high blood pressure, high cholesterol, diabetes and even some forms of cancer. Despite these dangerous health possibilities, treatment of obesity has been difficult. Prescription weight loss medications like the formerly popular Reductil or currently available Xenical are usually only prescribed if dietary changes and exercise have proven ineffective. And while they assist with weight loss, they are not completely addressing the condition.

However, a new study into the genetics involved in obesity may provide more targeted ways of reducing excess weight.

The study was published in the journal Nature Medicine and focused on how the message to “stop eating” was effectively being blocked by a specific genetic mutation. The research team from the Georgetown University Medical Centre studied laboratory mice which had the mutation, compared with those that maintained this genetic function, to pinpoint the difference.

Results were resoundingly clear as the mice who suffered from the mutation consumed nearly 80% more food than normal during testing. The reason being that overall, the rodents that had the genetic difference showed a significant alteration in brain response to appetite hormones. As hunger and appetite are regulated by hormones, such as insulin and leptin, any disruption would potentially lead to over consumption as the urges are not satiated properly.

“If there is a problem with the BDNF gene (where the mutation was examined), neurons can't talk to each other, and the leptin and insulin signals are ineffective, and appetite is not modified,” said Professor Baoji Xu, one of the researchers who took part in the study. “[Results] may open up novel strategies to help the brain control body weight.”

These could include new approaches to dieting, focusing on foods that help reduce appetite and help counteract the possible mutation. It could also lead to the development of new prescription medication, as previous prescription treatments, like Reductil, had failed to appropriately reduce appetite safely. This form of medication is of particular interest to people wanting to lose weight and treat obesity, as they require little alteration to their lifestyles.

While this is a positive step forward in the fight against obesity and excessive weight, including more research into human genetics in relation to the condition, experts did however caution that this study was purely connected to mice and is not conclusive for humans as of yet.